If you do not have the AutoDiscover CNAME configured for domain, please review our settings Here.
1. Open your Outlook 2013 Client.
2. A the top of the ribbon click the Send/Receive tab.
3. Within the Ribbon, click the small drop down menu for Send/Receive Groups and choose Download Address Book.
4. A new window will appear. Within the Offline Address Book window, confirm the check-box Download changes since last Send/Receive is enabled. By default, your organization's Global Address List is selected. Choose the Offline Address Book you wish to Download and click OK.